The present invention relates to a semiconductor device including a semiconductor element which may change in characteristics due to the effects of light.
As examples of a semiconductor element which may change in characteristics due to the effects of light, a metal-oxide-semiconductor (MOS) transistor, a nonvolatile memory including a floating gate, and the like can be given (JP-A-2000-286383). The characteristics of these semiconductor elements may change due to the effects of light. For example, the ON/OFF characteristics of the MOS transistor may change, or electric charges injected into the floating gate of the nonvolatile memory may be removed. In particular, the effects of light must be taken into consideration when a chip is mounted by a COG mounting method or the like (e.g. bare chip).
In order to prevent such a change in characteristics of the semiconductor element, a light-blocking layer for blocking light is provided over the semiconductor element.
However, while the light-blocking layer can block light entering from the upper side of the semiconductor element, it is difficult for the light-blocking layer to block light entering in the direction parallel to the formation surface of the semiconductor element. In order to minimize the amount of light entering in the horizontal direction, a light-blocking material (e.g. metal interconnect) having a light-blocking area sufficiently greater than the area of the formation region of the semiconductor element must be provided in the light-blocking layer. This prevents efficient utilization of the chip area, whereby a reduction in cost is hindered.